Regulation of the transcription of genes encoding different virulence factors in Helicobacter pylori by free iron

FEMS Microbiol Lett. 1999 Jun 15;175(2):165-70. doi: 10.1111/j.1574-6968.1999.tb13615.x.


Since free iron possesses a poor solubility under physiologic conditions and thus becomes a limiting nutrient for growth, a shift from high- to low-iron environmental conditions is an important signal for bacteria to coordinate the regulation of gene expression. Here, we studied and compared the level of transcripts corresponding to the vacA (cytotoxin), ureA (urease), cagA (cytotoxin-associated antigen) and fur (ferric uptake regulator) genes of Helicobacter pylori, grown under iron-sufficient and iron-restricted conditions. A significant increase in the accumulation of vacA and fur transcripts was observed under iron-restricted conditions. This up-regulation by low levels of iron seems to be not directly regulated by Fur, and certainly requires other regulatory factors. No statistical difference was defined in the accumulation of cagA and ureA.

MeSH terms

  • Antigens, Bacterial*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Blotting, Northern
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial
  • Helicobacter pylori / genetics*
  • Helicobacter pylori / growth & development
  • Helicobacter pylori / pathogenicity*
  • Iron / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Transcription, Genetic
  • Urease / genetics
  • Urease / metabolism
  • Virulence / genetics


  • Antigens, Bacterial
  • Bacterial Proteins
  • Repressor Proteins
  • VacA protein, Helicobacter pylori
  • cagA protein, Helicobacter pylori
  • ferric uptake regulating proteins, bacterial
  • Iron
  • Urease